1. Field of the Invention
This invention resides in the field of crude oil and crude oil fractions, and particularly petroleum residuum fractions. In particular, this invention addresses reformation processes for deriving usable oil from, or increasing the usable oil that can be extracted from, petroleum residua.
2. Description of the Prior Art
Crude oil is the largest and most widely used natural resource in the world, serving as a source of a wide range of fuels for consumer and industrial use as well as chemicals for use as raw materials in products used every day worldwide. Petroleum residua (or “resids ”) are the heavy fraction remaining after petroleum crudes are distilled at atmospheric pressure or at reduced pressure, i.e., the residue left after the most readily accessible components of the petroleum are extracted. Resids are highly complex in composition, including components of high molecular weight as well as polynuclear aromatics, coke, asphaltenes, resins, small ring aromatics, and saturates. Unfortunately, resids are of extremely limited utility. A variety of conversion processes have been developed to increase the utility of, or obtain useful products from, resids. These processes include separations, thermal conversion, hydroconversion or hydrotreating, and fluid catalytic cracking. The processes that are the most economical, however, result in a carbonaceous byproduct that is even heavier than the starting resid, including further formation of polynuclear aromatics. Processes that involve the use of catalysts are also costly due to the cost of the catalysts themselves and the expense of recovering and recycling the catalysts after use. Also, the petroleum industry is continually seeking ways to utilize resids of lower quality and lower cost due to a continual need for new sources of crude oil and to continuing pressure from the public and regulatory agencies to make use of these resids rather than to dispose of them. As a result, processes that can economically and effectively convert these resids to lighter components are continually needed.